Author Topic: vg mini design  (Read 3443 times)

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Offline windswept

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vg mini design
« on: January 07, 2007, 02:23:21 AM »
   Came across these drawings for new design from vg design.
  any opinions  on the hull shape and fine bow sections . 
www.vgyd.com/vgmini_drawingboard.html

Offline Zimonem

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Re: vg mini design
« Reply #1 on: January 07, 2007, 09:46:28 AM »
well, if you are a wannabe minist, you ahve to ask yourself a question "which boat i want?" and immediately the next question follows "which boat can i afford?"
if positive on both  answers, then the next question is what would be a competition advantage of a design which did not do anything noticable, is clearly out of sync with lattest generation of minis, either in shapes, volume distribution, weight, etc...
but if you don´t have money and they give you an offer you can´t refuse - then go for it. Even a bad day at mini is better than a good day at your office.

Offline Reddy

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Re: vg mini design
« Reply #2 on: January 07, 2007, 16:38:45 PM »
Being new to the Mini. Could you just outline what the new trends are to the modern design and ideas. I would think the following are good areas to discuss.

Hull design Hard chine verses rounded
Bow  area - fine entry verses fuller forward
Aft section
Deck joint - rounded or angular
Hull Materials
Displacement  I see range from around 800 kg to production boats at 1100kg
Rig - spreader configuration etc
Daggerboards one or two
keel - canting and fore and aft adjustment
Water balast

Thanks


Randy

Offline NicoG

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Re: vg mini design
« Reply #3 on: January 07, 2007, 17:19:03 PM »
Ok will give it a go:

Hull design Hard chine verses rounded

newest is to have a chine, claims to be more powerfull, and a good one will work, but still it aint magical. And you can overdo it too, JK claims his were to big on the VOR 70.

Bow  area - fine entry verses fuller forward
not much going on here.

Aft section
not much going on in this.

Deck joint - rounded or angular
that depends on building process, there is not a real advantage or disadvantage for this.

Hull Materials
Nothing new here too, carbon nomex can be risky as the builder has really be good.
Foam takes that worry away.

Displacement  I see range from around 800 kg to production boats at 1100kg
Never believe those numbers,
ask hull/deck structural weight, bulb weight and foil weight.
Overall a min can weigh 750 kg i believe...

Rig - spreader configuration etc
thats fashion, your personal preference, nothing really mathematical.

Daggerboards one or two
Two for most, better in rougher weather.

keel - canting and fore and aft adjustment
Just canting is a good place to start, the sliding one ifs for very good tweaky sailors...
in theory it works but in practice... does it make your stacking lazier ???

Water balast
never bad to add, you do not have to fill it..

Oh and add rocker to the list... no rocker, no directional stab, to much rocker, slower.

oh to add, i think we are now seeing an era of refinement, no revolutions.
« Last Edit: January 07, 2007, 17:24:34 PM by Leov »

Offline andraz510

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Re: vg mini design
« Reply #4 on: January 07, 2007, 17:42:01 PM »
OK guys, some of my views on the topic...
The biggest change in Mini is by far preparation of sailors. You must notice 198 Brossard which is old Karen Liquid from 97 Transat, fited with new mast (and new extending keel but that is by my oppinion not decisive) still being competitive today. The boat is of course not bad, but the sailor and the Team Ocean is the one that makes it so dangerous.
Anyway...

Hull design Hard chine verses rounded - doesn't matter

Bow  area - fine entry verses fuller forward - look at next point

Aft section - more powerfull boats are the rule - new finot being most allround, but still much more powerfull than old one, Lombard and Manuard very powerfull.

Deck joint - rounded or angular - who cares. AC teams found out that angular makes better aerodynamics in combination with the jib, but in offshore world that is bunch of bollocks.

Hull Materials - didn't change for a while - vacuum baged carbon (mostly) + airex or prepreg and nomex (rare)
Displacement  I see range from around 800 kg to production boats at 1100kg - which displacement? empty, ready for jauge, transat ready? Lots of fog and bs in that departement. If you are not going for podium places not a realy important data, but hull+deck+structure of modern proto should be around 300kg.

Rig - spreader configuration etc - everything goes if it is well made. Autoclaved tubes with no, one or two spreaders are more or less curent trend in top protos. Unidirectional PBO aswell.

Daggerboards one or two - all new boats go for two, but Brossard is doing quite well (2nd fastnet, 1st Acores...) with one.

keel - canting and fore and aft adjustment - Canting of course, fore and aft is speciality of rogers (and 424 De la Motte design). No top boats uses that. Brossard as only one goes for extending.

Water balast - a lot, up to 180 liters lateral with canting keel. A lot of experimentation with position and shape of tanks.

But again the most noticable and performant trend is training of the sailors. You see poles (training programs) emerging from every bush. Sail programs are more and more elaborat and sailors push boats harder and harder. I know that is quite unpopular view since it is very difficult to admit that the problem of average results usualy lies in sailor and not his equipement but that doesn't change the facts.

PLP
Andraz

Offline Reddy

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Re: vg mini design
« Reply #5 on: January 07, 2007, 19:58:23 PM »
Gentleman, Thank you for the experienced feedback. I think in general this is a very good topic area to help build interest in North America. Let me digest your feedback, I will have questions. I like your last comments Andraz. I have been racing for many years and its not always the most high tech boats that win. Sailing ability and going the right way makes a huge difference. All one has to do is look at results of the Protos and the production boats to tell you that.
There is often not much of a spread once you get below 3rd place or so.

Thanks again
Randy

Offline GDesign

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Re: vg mini design
« Reply #6 on: January 07, 2007, 21:30:57 PM »
From my point of view ..

Hull design Hard chine verses rounded

Chine can be more powerful, you can get less wetted surface area up right and a clear advantaged when heeled

Bow  area - fine entry verses fuller forward
There is a thing going on there... boats with very thin entry, concave water line at the bow will create high hydrodynamic resistance at high speeds and would be better at low speeds..
minis tend to rise their bows when reaching so, i would go for a fair entry line... (not concave as it is shown on the vg design)

Aft section
Flat, this will give you a planning area.

Deck joint - rounded or angular
Although it depends on how is built, the point on rounded edges (big radius) is to reduce capsizing due to deck immersion. It is proved it is beneficial, but.. what’s the real advantage?.... i think is a personal call but i think it is not worth for such a small boat.

Hull Materials
Idem as above. Plus hull foam count towards your flotation volumes.

Displacement  I see range from around 800 kg to production boats at 1100kg
shown numbers are design numbers, depends on loading conditions etc.

Rig - spreader configuration etc
Rig... more spreaders, less mast cross section section hence less windage, but more coming from your rigg and spreaders..
there is an advantage on configuration but, it is a personal call..
more parts, more things can go wrong.. plus it takes quite an analysis to evaluate windage and performance of the rig! (and you have to be such a good sailor to take advantage of this!)

Daggerboards one or two
Two gives better up wind performance but more weight.

keel - canting and fore and aft adjustment
Canting is a must... the rest comes with experience.

Water ballast
Can be always added later... i wouldn’t worry to much about it as a start.

Rocker...
As said...some is needed...

Minis shape is pretty defined, keys are in rocker, balance, appendages and mainly sailing hours, getting the feel of your boat and knowing its limits and key points can make the difference.

Offline NicoG

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Re: vg mini design
« Reply #7 on: January 08, 2007, 00:31:45 AM »
Qoute:

Hull Materials
Idem as above. Plus hull foam count towards your flotation volumes.

I thought only the foam in the deck, but have to download the rules again...

Oh and rocker i think leads to how the bow will dive in waves too, and to thin bows do not help for that too. Nosediving can be one of the problems you have to think about...



Offline Reddy

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Re: vg mini design
« Reply #8 on: January 11, 2007, 22:56:39 PM »
Foam -What is the most common foam used in the hull and deck construction and what thickness?

Materials - Is Kevlar used much? I see some boats built this way. What would be the advantages of Kevlar?

Interior I know that ribs probably reduce weight and give a little more openness to the cabin but how do you keep equipment stored and in place without a few bulkheads and lockers. It must get funky down below on a crappy bouncy day.

Randy

Offline NicoG

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Re: vg mini design
« Reply #9 on: January 12, 2007, 16:01:05 PM »
Kevlar is shit for minis, lookup characteristics and you will understand.
Foam, pvc crosslinked most, San.

Interior, you need stacking areas...thats where the designer shows his experience too.